Further considerations on the Revised European-American Lymphoma classification

Stem Cell Transplantation for Chronic Lymphocytic Leukaemia: Is this the Way Forward in the New Millennium?; Malignancy; Current Clinical Practice

The failure of conventional chemotherapy to eradicate chronic lymphocytic leukaemia cells and induce cure has led many clinicians to investigate the use of high dose chemotherapy and haemopoietic stem cell rescue in this disease. The selection of patients remains a major problem because this is a disease of elderly patients with a median overall survival of 7 years and will only therefore be applicable to a minority of patients. However transplantation is the most likely therapeutic option at this time to lead to cure in this condition. The best type of transplant is not known and not all patients will be able to mobilise adequate numbers of stem cells or have a suitable donor identified. Autologous transplantation relies on the ability of high doses of chemotherapy to eradicate disease whilst allogeneic transplantation attempts to harvest the graft versus leukaemia effect that has been identified in chronic granulocytic leukaemia. However, the high treatment related mortality and morbidity of allogeneic transplants has led to interest in the use of non-myeloablative allografts which hope to maximise the immunological effects of transplantation to achieve durable remissions. To date there have been no randomised clinical trials to compare the efficacy of combination chemotherapy, autologous or allogeneic transplants and this is unlikely to happen in the near future. Other issues that need to be addressed include the timing of transplantation, the source of stem cells, the optimal conditioning regimen and the role of immunomodulation post transplantation. This review attempts to answer some of these questions.

Allogeneic stem cell transplantation for the non-Hodgkin's lymphomas and Hodgkin's disease

Certain poor-prognosis patients with non-Hodgkin's lymphoma and Hodgkin's disease, usually with recurrent and/or refractory disease, are rarely curable with standard chemoradiotherapy. Autologous hematopoietic stem cell transplantation has been shown to result in improved long-term disease-free survival in some of these patients. Unfortunately, a number of patients are not suitable for autologous transplantation due to a damaged stem cell pool involvement or other disease processes of the marrow. These patients may benefit from allogeneic stem cell transplantation. In addition to the therapeutic effect of high-dose chemotherapy with or without total body irradiation, an immunologic [i.e. graft-versus-lymphoma (GVLym)] effect may be present in some patients undergoing allogeneic transplantation, resulting in a lower relapse rate than autotransplants. However, allografts are almost always associated with a higher non-relapse mortality due primarily to graft-versus-host disease (GVHD); unfortunately, GVHD and GVLym are difficult to separate. Thus, full exploitation of this GVLym effect may require the modification of commonly used conditioning regimens; if successful, these modifications may allow an additional decrement in the incidence of relapse without additional morbidity. Also, when combined with lesser intensity conditioning, such may permit patients who otherwise would not be candidates for standard transplant regimens to be allografted.